Battery drains while parked under the hot sun

Yes, it does have solar roof. It's been rainy and overcast here lately but today is supposed to be sunny I believe. I will make note of my observations for a couple of days and update later.

 

We spent a lot of time in Florida last year... really hot humid 90s daily down there, cooling fan ran all the time while parked... never saw battery drops of any sort. Even while parked for 2-3 days.

In urban and suburban driving, our Prius was maintaining 61+ mpg, the best I've seen for a prolonged period (ended up with a tank to tank calculated 58.3 mpg). "Cold" tire pressures 40 psi front, 38 rear. Prius had about 32-33k miles at that point.

 

Sounds like the car is not completely turned off. Maybe a weird malfunction of a relay?

 

I know mine was powered down. Doubt anything would be wrong with 1500 miles I'll do some tests this season when I get a chance to take it out of storage. I did buy license tabs so I have to drive it at some point this season or my wife won't be too happy

Mike

 

It is under some floor dress panel, but it is actually in the cabin interior. We have had a few prior cases where cars parked in hot sun all day had restricted battery operation -- e.g. no EV, no auto-shutoff of ICE when it normally should, poor acceleration and mpg -- that was remedied once enough cabin AC had been pushed through the battery.

Yes, this will help with diagnosis.

It is supposed to be disconnected. In OPs case, it seems that this is a possible trouble spot to be checked out.

 

Interesting post. I've never noticed a huge drop like the OP is describing, but in the first 1500 miles or so I did notice a consistent 2 bar drop whether the car was left overnight (relatively cool) or while I was parked at work during the day (relatively hot). Since then I've made it a habit to use as much of the battery as I can in the 2 miles between the Highway and my house (or office). If I leave it at 2 or 3 bars it never shows different when I return.

In the end the issue is likely an inaccuracy in the more full readings that corrects itself after the car has cooled down and been restarted.

 

Wonder if it is runnin the A/C or maybe a software bug I will take my car out of storage in July or maybe the last week of June and do some testing too

Mike

 

Here's my little update now that we've had some nice (non-rainy) weather. I have noticed once that it seemed the battery was drained a little between the morning and lunch time on an exceptionally hot day, 91 degrees. Then from lunch to quitting time it was fine. I'm going to keep testing it and see.

 

Sure. Just to clarify you mean something like this: Run AC and leave the switch in on position then turn off the car when parked as usual. By AC off don't run the AC and make sure the switch is in the off position before turning off the car when parking. Did I understand you correctly?

Edit to add: I'm going to don my white lab coat (I actually have one from my pharmacy technician days in college) and make sure to account for the biggest variable, weather. I'll toss a small notepad in the car and jot down the temperature, sunny/cloudy and number of dashes (ticks, slots, whatever they're called) on the battery and AC on/off. That should give a good set of results.

 

I leave my windows open.

 

Thanks for the update. Things like that turn to be user errors.
I did some crazy things too when I was new to prius. Like stepping out of car, noticing it's still on and in drive, and chasing it.

 

Good thing it is so slow!

 

Interesting....my mileage seemed to pop-up right around 3K miles as well (and with no change in driving behavior).

 

I'm glad your 2014 Prius is OK now.
A door stayed open or a dome light on could have been the cause!!
Thanks for the update.